Low-current polysilicon fuse

Abstract

A submicron-width fuse element is disclosed that protects peripheral DRAM chip devices from low current failures below the range of metal fuse elements. In a specific application, the fuse elements are used to protect a DRAM chip from dielectric failure of voltage supply filtering capacitors. A low cross-section and length allows minimum space for the element.

What is claimed is: 
     
       1. In an integrated circuit semiconductor chip, a low-current, interrupting, polysilicon fuse for protecting a peripheral noise-filtering capacitor comprising: a. a first electrical conducting means connecting to the capacitor;   b. a reduced cross-section fuse element of about 2.5 μm length, 1.5 μm width, 0.63 μm height, and 90 ohms resistance, planar with the capacitor connecting to the first conducting means; and   c. a second fuse conducting means connecting to the fuse element and connecting by a plurality of contacts to a power supply conductor wherein the fuse element, fuse conducting means, and electrical device consist of a top layer of polysilicon, a middle layer of tungsten silicide, and a bottom layer of silicon oxide, and wherein a low but destructive current of about 24 milliamps within the capacitor causes current interruption by the fuse element, thereby preventing chip failure.   
     
     
       2. In an integrated circuit semiconductor chip, a low-current, interrupting, polysilicon fuse for protecting a chip peripheral, noise-filtering capacitor comprising: a. a first electrical conducting means connecting to the capacitor;   b. a reduced cross-section fuse element of about 2.5 μm length, 1.5 μm width, 0.63 μm height, and 90 ohms resistance, planar with the capacitor connecting to the first conducting means; and   c. a second fuse conducting means connecting to the fuse element and connecting by a plurality of contacts to a power supply conductor, wherein the fuse element, fuse conducting means, and capacitor consist of a top layer of polysilicon about 1800 Å in height, a middle layer of tungsten silicide about 1200 Å in height, and a bottom layer of silicon oxide about 3300 in Å height and, wherein a low but destructive current of about 24 milliamps within the capacitor causes current interruption by the fuse element, thereby preventing chip failure.   
     
     
       3. In an integrated circuit semiconductor chip, a low-current, interrupting, polysilicon fuse for protecting a peripheral noise-filtering capacitor comprising: a. a first electrical conducting means connecting to the capacitor;   b. a reduced cross-section fuse element of about 2.5 μm length, 0.6 μm width, 0.63 μm height, and 50 ohms resistance, planar with the capacitor connecting to the first conducting means; and   c. a second fuse conducting means connecting to the fuse element and connecting by a plurality of contacts to a power supply conductor wherein the fuse element, fuse conducting means, and electrical device consist of a top layer of polysilicon, a middle layer of tungsten silicide, and a bottom layer of silicon oxide, and wherein a low but destructive current of about 38 milliamps within the capacitor causes current interruption by the fuse element, thereby preventing chip failure.   
     
     
       4. In an integrated circuit semiconductor chip, a low-current, interrupting, polysilicon fuse for protecting a chip peripheral, noise-filtering capacitor comprising: a. a first electrical conducting means connecting to the capacitor;   b. a reduced cross-section fuse element of about 2.5 μm length, 0.6 μm width, 0.63 μm height, and 50 ohms resistance, planar with the capacitor connecting to the first conducting means; and   c. a second fuse conducting means connecting to the fuse element and connecting by a plurality of contacts to a power supply conductor wherein the fuse element, fuse conducting means, and capacitor consist of a top layer of polysilicon about 1800 Å in height, a middle layer of tungsten silicide about 1200 Å in height, and a bottom layer of silicon oxide about 3300 Å in height, and wherein a low but destructive current of about 38 milliamps within the capacitor causes current interruption by the fuse element, thereby preventing chip failure.